1. Field of the Invention
This invention relates in general to boats for use in the sport of water skiing. More particularly, the invention relates to apparatus and method of operation for controlling the wake in water behind ski tow boats of the type which include an inboard power plant and a flat bottom hull.
2. Description of the Related Art
In the sport of water skiing, the water skiers are pulled through the water by boats which create wakes. Family or novice skiers desire a flat wake that they can cross as they are pulled through the water at relatively slow speeds. More athletic or competitive skiers desire larger wakes which they can cross while performing acrobatics. The relatively recent introduction of wake boards and knee boards have introduced styles of water skiing where the enthusiasts desire large wakes which can be used to perform jumps into the air.
Various types of power boats have heretofore been used for towing water skiers. These include trailable boats which typically are 25' and under in length and which are powered either by outboard motors or by inboard engines with propeller drive units. The majority of these types of boats have a hull with a deep V-shaped cross-section. In this type of power boat, it is desirable to quickly get the front end of the hull out of the water at a higher angle of attack as the boat accelerates to cut down on drag and allow the boat to go much faster. This causes the stern of the boat to sit down into the water so that it effectively digs a trench along the path that it makes through the water, which in turn produces bigger wakes.
Conventional power boats have been fitted with adjustable trim tabs on port and starboard sides of the stern transom, as for example the boat shown in FIG. 1. In the boat of FIG. 1, a pair of adjustable trim tabs 10 and 12 are mounted on the bottom of the stern transom in a manner described in U.S. Pat. No. 5,058,520. Hydraulic actuators 14 and 16 are mounted between the transom and tabs to conjointly pivot the tabs up or down under control of the boat operator. When the tabs are conjointly moved down, they help get the boat up on plane faster. The tabs can also be moved independently to correct any left-to-right lean or roll of the boat about its longitudinal axis. Appropriate adjustment of the trim tabs is made for trimming the boat for reasons such as better fuel economy.
Ski tow boats known as tournament boats have become popular for competitive skiing. Tournament boats are inboards which have relatively low top speeds of up to only about 50 mph. The lower speeds are due to the fact that the hulls run "wet", meaning that they have a relatively high drag. The hulls do not have a deep V-shaped hull design as in conventional power ski tow boats. Instead they have hulls with a cross-section which has a V-shape at the bow that merges amidship into a flat or semi-flat bottom at the stern. Such a flat or semi-flat stern bottom design allows the hulls to run with a greater surface area along the top of the water which produces the higher drag. The hulls of tournament boats when run at speed do not lift with a high angle of attack characteristic of deep V-shaped hull boats, and thus produce smaller wakes. Prior art tournament boats have not been capable of selectively changing the size of the wake so the boat can be used by a range of skiers having different skills and sporting tastes.
The need has been recognized for a ski tow boat which obviates the foregoing and other limitations and disadvantages of prior art ski tow boats. Despite the various ski tow boats in the prior art, there has heretofore not been provided a suitable and attractive solution to these problems.